Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of materials over a semiconductor wafer, and patterning the various material layers using lithography to form circuit components and elements thereon.
The semiconductor industry continues to improve the integration density of various electronic components (e.g., transistors, diodes, resistors, capacitors, etc.) by continual reductions in minimum feature size, which allows more components to be integrated into a given area. These smaller electronic components also require smaller packages that take up less space than the packages used in the past, in some applications.
During the manufacturing of the semiconductor devices, various processing steps are used to fabricate integrated circuits on a semiconductor wafer.
As semiconductor technologies evolve, advanced lithography techniques have been widely used in today's integrated circuit fabrication processes. Photolithographic techniques involve forming a photoresist layer over a substrate, exposing portions of the photoresist material to a pattern of light in accordance with a desired pattern, developing the photoresist material to remove portions of the photoresist material to expose portions of the underlying material. A suitable etching process such as dry etching, wet etching and/or the like may then be performed on the substrate. As a result, the exposed underlying material may be removed in accordance with the desired pattern.
The exposure step of the lithography process may involve a variety of reticles (such as photomask). The lithography process of the integrated circuit may comprise multiple photolithography process steps due to the complexity of the manufacturing process. Each lithography step may employ a reticle through which the pattern of a component of an integrated circuit is generated.
Although existing lithography systems and processes have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.